Seeds of Calotropis procera Treated With Essential Oils of Copaifera langsdorffii Desf. and Syzygium aromaticum L.

Abstract

The Silk Flower (Calotropis procera) is widely used by farmers in the Northeast region, due to the adaptation of the climatic and soil conditions of the semi-arid region, but the incidence of pathogens has reduced the physiological and sanitary quality standards acceptable for sexual propagation of these plants in the field. Thus, the objective of this research was to verify the effects of the Copaíba (C. langsdorffii) and Cravo (S. aromaticum) oils on the health and physiological quality of silk flower seeds (C. procera) harvested in the city of Tacima, PB. The treatments were constituted by Copaíba (C. langsdorffii) and Cravo (S. aromaticum) essential oils at concentrations of 0.5; 1; 1.5; 2% and the fungicide Captan® (240 g, i.a. 100 kg-1 seed). The control 0 (zero) corresponded only to the immersion of the seeds in distilled and sterilized water (ADE). In the evaluation of sanity, the method of incubation on filter paper (Blotter test) was performed, using twenty replicates of 10 seeds for each treatment. The physiological quality was evaluated by the germination test (G%), first germination count (FGC), germination speed index (GSI) and seedling dry mass (SDM). A microflora composed mainly of Alternaria sp. (52%), Fusarium sp. (70%), Helminthosporium sp. (40%), Cladosporium sp. (50%), Curvularia sp. (20%) and Nigrospora sp. (5%). The essential oils considerably reduced the percentage of fungi associated with silk flower seeds, but there was moderate phytotoxic effect under the germination and vigor of C. procera seeds.